The present invention relates generally to devices that can be used to control the light output of light sources. More particularly, this invention pertains to a device that can be used to control the light output of a light emitting diode light source.
Light emitting diode (LED) light sources are known in the art. For example, the prior art teaches the use of LED traffic signal devices. These devices are typically designed to be connected to an ac power source and include an ac to dc converter that converts the ac power supplied to the device into dc power. This dc power is then used to power an array of LEDs included in the device.
The various benefits of LED based traffic devices are well known in the art. LED traffic devices consume less power than their incandescent traffic device counterparts. In addition, LED traffic devices have longer usable life spans when compared to their incandescent traffic device counterparts.
LED traffic devices, however, do have one specific disadvantage that is addressed by the present application. These devices generally include a plastic lens that is used to enclose the LEDs used in the LED traffic device. This lens degrades over time and, as a result, reduces the effective light output of these devices. This is an undesirable condition because it makes it difficult for automobile drivers to see the traffic signals generated by the LED traffic device.
A review of the prior art relating to LED traffic devices indicates that there does not appear to be any suitable solution to this problem.
What is needed, then, is some type of device that can be included with an LED traffic device that compensates for this reduction in effective light output and ensures that the effective light output of the LED traffic device remains relatively constant over the lifetime of the device.